Installation for purifying spent fuel oil



R. SIEBENMANN 3,469,701

INSTALLATION FOR PURIFYING SPENT FUEL OIL Filed March 18, 1968 2 Sheets-Sheet 1 M l l l s R 1 J f y '7 V H h m se so, 19%

R. SIEBENMANN 3,469,701

INSTALLATION FOR PURIFYING SPENT FUEL OIL Filed March 18, 1968 2 Sheets-Sheet; 2

FIG.2

United States Patent @fice 3,469,701 Patented Sept. 30, 1969 3,469,701 INSTALLATION FOR PURIFYING SPENT FUEL GIL Richard Siebenmann, 6 Chemin de lUnion, 1008 Prilly, Lausanne, Switzerland Filed Mar. 18, 1968, Ser. No. 713,617 Int. Cl. B01d 21/02 US. Cl. 210-258 Claims ABSTRACT OF THE DISCLOSURE This disclosure concerns an installation for treating spent oils to render them suitable for use as fuel constituted by a decantation system divided into four compartments forming a progressive decantation chain, the spent oils passing during their treatment all or some of these compartments, characterized by the fact that the system is rectangular and is divided into two parts divided in two by a wall which is oblique at least on its greater part, the oblique walls converging each upwardly toward the corresponding lateral wall of the cistern in order to form a first compartment contiguous to one of the lateral walls of the cistern, the second compartment contiguous to the other lateral wall of the cistern, a third compartment located between the transversal wall of the cistern and the second compartment and a fourth compartment between the first and the third compartment, intended respectively for sand and other particle removal, for the removal of water and of oily mud, for an intermediate decantation and for the finish of the decantation and the storage of the decanted oil.

The present invention is concerned with an installation for treating spent oils to transform them into fuel oil which burns cleanly and which may be used in normal high presure burners fitted with pre-heating means.

The installation according to the invention is monolithic and makes it possible to perform an effective and systematic treatment upon the spent oils on a site having a reduced surface area.

The accompanying drawing represents by way of example one modification of the invention.

FIGURE 1 is an elevational view of the installation.

FIGURE 2 is a cross sectional view taken along line IIII of FIGURE 1.

FIGURE 3 shows schematically the oil circulation in the cistern.

As above stated, the treatment installation is a monolithic whole and comprises all the elements necessary for its operation.

It comprises essentially a rectangular cistern I mounted on a concrete base 2 having horizontal dimensions corresponding to those of cistern 1. Cistern 1 is divided into four compartments 1, II, III and IV by a vertical wall 3 parallel to the lateral walls 4 and 5 of the cistern and by two walls 6 and 7, disposed obliquely on their greater part, only the upper part 6a, and 7a respectively, of these walls being vertical. Compartments 1 and 2 accordingly narrow towards the bottom while compartments 3 and 4 on the contrary expand toward the bottom. These characteristics are important as will be seen later.

The volume of compartments I, II, III is equal respectively to /s the total volume of cistern 1, while the volume of storage compartment IV represents /5 of the total volume.

Each of compartments I to IV comprises a drainage opening 8, 9, 10 and 11 located on a level with bottom 12 of the reservoir which constitutes the common bottom of the four compartments. In order to permit the flow of the residue toward the drainage openings, this bottom 12 has an inclined plane. Compartment I contains additionally an endless screw 13 occupying nearly entirely the bottom of the compartment between walls 5 and 6 and serving to evacuate the residue forming in compartment I toward drainage opening 8. The screw 13 is necessary to evacuate the sands and the metallic particles which are too heavy to fall by themselves toward drainage opening 8.

The installation comprises additionally a received bin 14 of reinforced concrete, shown in cross section, projecting above the level of the ground by about 50 centimeters and covered by a grill 15 serving as a strainer during reception of the oils.

A transfer pump 16 mounted near bin 14 is intended for feeding the installation proper constituted by compartments Ito IV. Near compartment I, outside the perimeter of base 2, a bin 17 is made in the ground for the reception of drainage muds. Additionally, partially encased in the angle of base 2 is a special container 18 connected by a vertical conduit 19 to the base of compartment I, for the reception of the residue from this compartment. Conduit 19 can be closed by means of a valve 20. The recipient 18 being closed, there is connected to compartment I by tubing 21 having for its purpose to even out the pressure between compartment I and recipient 18 in order to ensure suitable flow of the residue.

In the concrete base 2 is positioned a control chamber 22 inside of which are located the various command and control members for the installation, including an electric panel, a valve panel, levelmeters and manometers, a circulating pump, as well as a boiler 23 intended to feed with hot water preheating elements 24, 25, 26 and 27 mounted respectively in each of compartments I, II, III and IV. The fuel burned in boiler 23 can consist of the oil treated in the installation.

The installation permits to obtain a rapid and complete decantation of the oils used. At the end of operation, these oils must be free of sand, mud, and metallic particles in order not to interfere with the operation of the burner during combustion.

Generally the spent oils will be treated successively in each of compartments I, II, III and IV. The sand removing operation is carried out in compartment I; the particular shape of this compartment makes it possible to accelerate the sand removal process as compared with vats previously employed. The known vats in effect have a rectangular cross section or a funnel-shaped cross section, that is to say two oblique walls. Compartment I has but a single oblique wall while the other wall 5 is vertical. The obtaining of a more rapid decantation can be explained in the following manner: the heavy particles have a tendency to go down vertically, that is to say along wall 5, while light particles have a tendency to go up along the inclined plane constituted by wall 6. There are thus established separate circulation currents, the elimination of an oblique wall diminishing additionally the frictional surface of the ascending particles, thus accelerating the decantation process by comparison with a V-shape or a rectangular shape for the vat.

The sand free oils pass next in compartment II intended essentially for the removal of water and of oily mud. For this purpose, compartment II has the same shape as compartment I, and the advantage obtained by the use of a single inclined wall 7 is the same as in the case of compartment I. The residue is evacuated by drainage opening 11.

The oils next pass into compartment III in which the decantation process ends and then accumulate in storage compartment IV which has a greater volume and in which a very slight decantation still takes place. The shape of compartments III and IV is particularly favourable for this. The total surface of the bottom of these compartments is in effect practically equal to the surface of the bottom of cistern 1, which allows the residue to spread out on a considerable surface. For a same volume as a compartment with vertical walls, there will be obtained a residue of lesser thickness on the bottom of the recipient, which will result in a better use of the compartment, the usable decanted oil reaching a lower level. Thus by dividing cistern 1 by means of oblique parti tions, there is obtained an optimal useful decantation surface in the four compartments, ensuring a more rapid and more complete decantation than that possible with known installations.

The passage of oil from one compartment to the other is achieved by means of a pump, a set of valves and piping. FIGURE 3 shows schematically the installation for circulating oil between the compartments. This installation comprises a circulating pump 28, a coarse filter 29 for protecting the pump and retaining sand and metal particles which might endanger the pump and a fine filter 30 which filters the oil before its entrance in the storage compartment IV.

The selection of the transfers from one compartment to the other is achieved by means of a set of valves 31, 32, 33, 34, 3S, and 36. Filters 29 and 30 are mounted in by-pass fashion by means of valves 37 and 38 and 39 and 40, respectively. Circulation takes place in the direction indicated by arrows along conduits 41, 42, 43, 44, 45 and 46.

Generally the oil passes successively through all compartments I to IV, that is from compartment I through conduit 43 through valve 37, coarse filter 29, valve 33,

pump 28, valve 36 and conduit 44 into compartment 11. Next it passes from compartment 11 to conduit 41, valve 31, pump 28, valve 35 and conduit 45 into compartment III. From compartment III, oil passes finally through conduit 42, valve 32, pump 28, valve 34, valve 39, fine filter 30 and conduit 43 into storage compartment IV.

This set of valves and the joints also make it possible to pass from one compartment to the other without following the normal sequence. It is thus possible to pass directly from compartment II through conduit 41, valve 31, pump 28, valve 34, filter 30 and conduit 46, directly into compartment IV.

Additionally, a direct connection is provided by means of a horizontal conduit 47 between compartment I and compartment II, this conduit connecting the upper parts of these compartments and making possible passage of oil from compartment I to compartment II by simple flow, when compartment I receives a large quantity of spent oil. Conduit 47 may be closed by means of a valve 48.

The most judicious circulation will be selected in proportion to the degree of impurities contained in the oil. In certain cases, passage through filter 29 can be avoided which accelerates circulation between compartments I and II.

Each compartment additionally comprises an aerating device, a pneumatic or electric levelmeter, a level indicator with a translucent tube and a manhole.

What is claimed is:

1. An installation for treating spent oils to render them usable as fuel comprising a decantation cistern with feed inlet means and efiluent outlet means, a vertical transverse wall dividing said cistern into two parts, a wall oblique at least on its greater part dividing each of said parts into two, the resulting oblique walls converging upwardly toward the transverse wall of said cistern so as to form a first compartment contiguous to one of the lateral walls of said cistern and converging towards the bottom, a second compartment contiguous to another lateral wall of said cistern and converging toward the bottom, a third compartment located between the transverse wall of said cistern converging toward the upper part thereof and said second compartment, a fourth compartment converging toward the upper part of the cistern between said first and said third compartment; means providing communication between the compartments and solids withdrawal means in each compartment.

2. Installation according to claim 1, wherein said cistern is positioned on a concrete base, means for actuating and controlling said installation being located inside said base.

3. Installation according to claim 1, wherein said first compartment has a drain and is traversed by an endless screw positioned at an incline at the bottom thereof parallel to the dividing walls and to the bottom of said cistern at the immediate vicinity thereof in order to drive sand towards said drain, the lower part of the oblique wall and of the vertical wall of said first compartment defining a housing having a width approximately equal to the diameter of said endless screw.

4. Installation according to claim 1, wherein said compartments are mutually connected by a network of pipes passing through an assembly of gates permitting connection of one of said compartments to any other compartment, there being a circulating pump for causing circulation of oil through said pipes.

5. Installation according to claim 1, having a horizontal conduit connecting directly said first and said second compartment in order to make possible oil flow from said first to said second compartment.

References Cited UNITED STATES PATENTS 1,775,233 9/1930 Brakensiek 210-259 X 2,756,965 7/1956 Howe 210--523 X 3,166,501 1/1965 Spohr 2l0259 X JAMES L. DE CESARE, Primary Examiner US. Cl. X.L. 

